Is the role of RATs (rapid antigen tests) being overstated? Given their inaccuracies, particularly early false negatives, their role seems pretty limited to a few specific situations. (Figure below from nejm.org/doi/full/10.10… ) Using RATs for omicron will miss folk in the first few days of infectiousness - so are no guarantee contacts or early symptomatic are not infectious. (Figure from medrxiv.org/content/10.110… compares RAT to PCR over 10 days)

Not “just a cold”: How does omicron compare to delta & influenza? Many confounders (detection, age, vaccination) so table is *rough* (thread->sources). Bottom-line: for unvaccinated omicron better than delta (~1/3 hospital/death) worse than ’flu. For vaccinated, less than ‘flu. 1/ Middle column Of Table (between delta & ‘flu) is derived from Gauteng data, where vaccination was around 31%.

How many #COVID19 cases are asymptomatic? The *incorrect* 40% figure keeps being repeated (such as claim below in 21 Oct NEJM Perspective), but best estimates are now closer to 17% based on systematic reviews of valid studies. 2/ There are 13 reasonably good studies of asymptomatic rates (checked everyone in a well-defined at-risk group & > 7 days follow up) when combined suggest a rate of around 17% - jammi.utpjournals.press/doi/pdf/10.313…

Asymptomatic #COVID19 has seen a lot of  disagreement this week: is it 15% or 40%? Is the transmission from asymptomatic people "very rare"? Some comments in this thread. @sophiescott2 @MelissaLDavey 1/ Important to separate (a) pre-symptomatic (= every infected person before symptoms!) from (b) asymptomatic throughout infection (so need follow up to check if symptoms develop - many studies don't) - which some commentary & reviews don't do.